Furnace-draft heater.



No. 687,564. Patented Nov. 26,'|90l.'

.J. B. HOUSTON. FURNACE DRAFT HEATER.

(Application filed Mar. 27, 1901.) (No Model.)

W/T/VESSES INVENTOH- JfiknBHouaian k m a 4770mm m: NORRIS PETERS cc. PNOYO-LITNQ, WASHINGTON, o. c.

:UNAITED STATES PATENT OFFICE.

JOHN BROADFOOT HOUSTON, OF VANCOUVER, CANADA.

'FU RNACE-DRAFT H EATER.

SPEGIFIOATION forming part of Letters Patent No. 687,564,;lated November 52 6,1901.

' Application filed March 27, 1901. semlitatai v. on main.)

To all whom it may concern:

Be it known that 1, JOHN BROADFOOT Hous- TON, a citizen of the Dominion of Canada, residing at Vancouver, in the Province of British Columbia, Canada, have invented a new and useful Furn ace-Draft Heater,of which the following is a specification.

My invention relates to improvements in the arrangement of the lines and divisions in that form of heateeonomizer wherein the products of combustion in their escape to the smoke-stack are'directed past air-jacketed fines and their connecting-tubes, through which the air for combustion is constrained to fiow on its way to the furnaces; and my aim has been to extract a maximum of heat from the escaping waste gases and to protect as far as possible such parts as are exposed to the direct heat by constructing them with air-spaces and insuring continual circulation of the air therethrough.

The accompanying drawings show the application of my system to a boiler of the ordinary marine type.

Figure 1 is a vertical section on the line a a. in Fig. 2; Fig. 2, a vertical section on the line b b in'Fig. 1; Fig. 3, a horizontal section on the line c'in Fig. 1; Fig. 4, a horizontal section onthe line d d in Fig. 1, and Fig. a cross-section on the line 6 c in Fig. 2.

In the drawings, B represents the front end of a boiler to which my system is applied, F F being the furnaces and T the return-tubes.

U is the uptake conveying the products of combustion to the smoke-stack S.

2 is the casing or wall of the uptake and smoke-box, and 3 the outer casing surrounding the same and providing it with an airjacket around front, back, and sides from the base of the smoke-stack to the reservoir R, adjacent to the furnace-front, which latter is of suitable construction to regulate the admission of the air for combustion to above and below the furnace-bars.

1 represents the tubes across the uptake from side to side, through which the air is circulated. and brought into more intimate relation to the heat of the escaping gases from the furnaces.

The air for combustion enters by the passage 4 and by means of the communication 5 is given direct access to the jacket opposite the point of entry. A partition on one side of the uptake divides the group of tubes 1 horizontally into two sections,'and divisions 29 on the same side out the lower section of the tubes off from direct access from the front and back jackets. On the opposite side divisions 26 cut the upper section of thetubes ofi from direct access from the frontand back jackets, and adivision 28 forms a chamber 27 around the ends of the tubes in the lower section and puts the section in communication with the front and back jackets by means of the passage 26. The efiect of these divisions is to cause the air entering the jackets by passages 4 and 5 to divide into two streams.

One stream flows across the back and front jackets to the right-hand side, through the upper section of the tubes to the left hand,

tween each nest of boiler-tubes, extending vertically from the bottom of the smoke-boxv to above the tubes 1, such plate being perforated to allow the tubes to pass freely through and is secured to boiler-front and inner walls of uptake, so as to brace and strengthen the structure. This division insures that the furnacegases shall flow uniformly among the group of tubes irrespective of the position of the smoke-stack in relation to the boiler. The lower part of this division, where it is exposed to the direct heat of the gases coming through the boiler-tubes, I make double, with an airspace 35 between the plates 33 and 34, and I connect this air-space 35 to the front or back jacket of the uptake, or both, by the apertures 36 or37 and enable the air to circulate through it by providing openings 38 into the reservoir R, adjacent to the furnaces. This construction not only lengthens the life of the division-plate 33 by preventing any excessive heating, but it incidentally secures better circulation through the lower parts of the uptake-jackets.

I am aware that prior to my invention the air for combustion in furnaces has been conveyed through the tubes and jacket-spaces exposed in the uptake, so that I do not claim such; but

What I claim as new, and desire tobe protected in by Letters Patent, is-

1. In a heat-economizer of the class described, an air-jacketed uptake, tubes across the same, a vertical division in the uptake having at a point below the tubes a double Wall, whereby an intermediate air-space is provided, said space being in communication with the main or furnace reservoir, for the purposes specified.

2. The combination with the jacketed uptake and the tubes across the same; of a division-plate extending from the bottom of the smoke-box above the top row of tubes, a series of division members at the sides and ends of the tubes in the offtake for deflecting the course of draft, and a passage 26 cooperating with the tubes and division members, all beuptake, the lower part of which below the tube group is made of two walls having an air-space between; means whereby air may be admitted from either front or back jacket or both, circulated through the air-space and allowed exit into the reservoir through the smoke-box-bottom, substantially as and for the purposes described.

4. In a heat-economizer of the class de scribed, the combination with an air-jacketed uptake having a group of horizontal tubes across it and means for conveying air for combustion to within such jackets and tubes; divisions in the jacket that shall cause the incoming air to divide and flow in opposite directions through the upper and lower tubeseotions and thence to the furnaces; a vertical division or divisions in the uptake comprised below the tube-sections of two walls with an air-space between, and means whereby the air may pass through this space between the jackets and the furnace-reservoir, substantially as and for the purposes described.

In testimony whereof I have signed my ing arranged substantially as shown and described.

3. In an economizer for heating the air for combustion in furnaces, the combination with a jacketed uptake and a group of tubes across it, of a vertical division or divisions in such name to this specification 1n the presence of two subscribing witnesses.

JOHN BROADFOOT HOUSTON. Witnesses:

ROWLAND BRITTAIN, ELLIOE WEBBER. 

